Colon cancer, commonly known as colorectal cancer or bowel cancer, is a cancer from uncontrolled cell growth in the colon or rectum, or in the appendix. See e.g., Cancer Genome Atlas Network, “Comprehensive molecular characterization of human colon and rectal cancer,” Nature 487: 330-337 (19 Jul. 2012). It is the second most frequently diagnosed malignancy in the United States and the second most common cause of cancer death. For example, the five-year survival rate for patients with colorectal cancer detected in an early localized stage is 92% while the survival rate drops to 64% if the cancer is allowed to spread to adjacent organs or lymph nodes, and to 7% in patients with distant metastases.
The prognosis of colon cancer is directly related to the degree of penetration of the tumor through the bowel wall and the presence or absence of nodal involvement. Consequently, early detection and treatment are important. Currently, diagnosis is aided by the use of screening assays for fecal occult blood, sigmoidoscopy, colonoscopy and double contrast barium enemas. Treatment regimens, as determined by the type and stage of the cancer, include surgery, radiation therapy and/or chemotherapy. Yet, recurrence following surgery (the most common form of therapy) is a major problem and often the ultimate cause of death. Despite research into therapies for the disease, colon cancer remains difficult to diagnose and treat. Thus, there is a need for new agents and methods for detecting and treating colon cancer.